Why sites outside Spencer Gulf were eliminated from the shortlist
During the shortlisting process, 10 areas were considered, including two which are outside the Spencer Gulf, along the Eyre Peninsula’s West Coast.
These areas (at Point Brown near Ceduna and north of Elliston) were assessed against the same criteria as areas within the Gulf, looking at availability of suitable land, access to good quality water supplies and how easy it would be to connect a desalination plant there to the existing and future water network.
The team also looked at the potential cost of building and maintaining a plant there compared to the proposed Port Bonython site which has been used as a benchmark due to its similarities with the NWS project.
Suitability of land and land impacts
Both the Point Brown and Elliston sites lack existing infrastructure (roads, power etc) and longer pipes are needed to deliver water to users due to the remote location. These sites also require a significantly larger clearance of native vegetation than other sites. The additional construction work required was also found to present a high risk of damaging sensitive local flora and fauna and of impacting sites of significance to both Aboriginal and European heritage.
Access to good quality water supplies
There are benefits to accessing an open ocean water source, which both sites have access to. Benefits apply to both the water treatment process and mixing of the concentrated seawater that is returned to the ocean. These were factored into the assessment.
It was identified, however, that the large swells and high energy ocean conditions would introduce a risk for construction work. This significantly increases the complexity and cost of construction and future maintenance of infrastructure at these sites and limits windows where this can occur.
Connecting water supplies to users
The largest users of the desalinated water produced by the NWS project are in the Upper Spencer Gulf and far north (cities of Whyalla and Port Augusta and mines at Olympic Dam and Carrapateena) so any delivery pipes would need to be significantly longer than the sites located within the Gulf.
In the case of Ceduna, pipes would need to be twice as long. There is no suitable existing water delivery network in this area which we could connect to. These longer pipes would create a significant impact on the local environment during and beyond their construction such as the need for more energy and construction materials (such as concrete and steel). The additional impacts can be avoided by locating a plant closer to where the water is needed.
In addition to the connection of the water infrastructure, it was identified that the Ceduna and Elliston sites would require more extensive road construction and larger changes to the state’s electrical network than a site within the Gulf.
Given the complexities outlined above and the lack of existing roads and other infrastructure (including access to a power network) in these two areas, it was found that that the cost for building and running a plant at either of these sites would be significantly higher (over $2-3 billion more) than the Port Bonython site or any of the other sites on the shortlist.
Consultation has concluded. Thanks for your contributions.